Fetal heart rate and patterns of such can reflect the wellbeing of the fetus. There usually is an increase in fetal heart rate associated with fetal movements, and physicians have been using this association, as well as the fetal heart rate variability, to assess the wellbeing of the fetus through a test called non-stress test. Fetal heart rate responds to stress caused by uterine contractions and other factors during labor.
Intrapartum electronic fetal monitoring is based on the study of the fetal heart rate patterns. Clinicians also study the fetal heart rate response to induced uterine contractions during a contraction stress test to assess fetal wellbeing. Most of the fetal heart rate monitoring is done using non-invasive sound wave based devices on the maternal abdomen, which can have difficulties in capturing fetal heart rate during uterine contractions and maternal movements. A fetal scalp electrode to capture fetal electrocardiogram (ECG) can only be applied after the rupture of membrane of the gestational sac, and it is invasive. There is a need for a more reliable way to capture and monitor fetal heart ratenon-invasively.